11. This improves the drainage from the pulmonary veins , and signs and symptoms of pulmonary congestion will decrease. 12. In the "'left heart "', oxygenated blood is returned to the left atrium via the pulmonary veins . 13. The principal problem with catheter ablation for AF is the failure to create lasting pulmonary vein isolation. 14. The left atrium receives oxygenated blood back from the lungs via one of the four pulmonary veins . 15. The oxygen-rich blood returns to the heart via the pulmonary veins to be pumped back into systemic circulation. 16. For orientation, the left atrium is identified by the presence of the septum primum and the pulmonary veins . 17. This increase in volume or pressure backs up to the left atrium and then to the pulmonary veins . 18. The thoracic operation consists of an extensive paraesophageal devascularization up to the inferior pulmonary vein and esophageal transection. 19. In the " left heart " oxygenated blood is returned to the left atrium via the pulmonary vein . 20. Below, it is joined to the upper left pulmonary vein by the ligament of the left vena cava.
